Ember Island is at the bottom right hand corner of the Southwestern map.
its on the southwestern sea chart or almost directly left from fire island
it is a mode unlocked on freedles island where with another player of phantom hourglass can trade items with you
Yes,you can find items on mercay island for phantom hourglass,in the temple of the ocean king.You can find the the southwestern sea chart (no requirements),the phantom hourglass,the northwestern sea chart (after you beat the temple of fire for both),the southeastern sea chart and the northeastern sea chart (after you beat the ghost ship for both).
Blaaz
Molaida Island
you get the hammer in pyramid island
On the island of ruins
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Cannon island
In Link and the legend of Zelda, Phantom Hourglass, you get the hammer in the isle of ruins, or the island of the dead.
I think the island's called 'Anouki Island'.
harrow island is in the southeastern sea.